com.google.javascript.jscomp

Class Scope

java.lang.Object

com.google.javascript.jscomp.Scope

All Implemented Interfaces:

StaticScope

Direct Known Subclasses:

TypedScope

public class Scope
extends java.lang.Object
implements StaticScope

Scope contains information about a variable scope in JavaScript. Scopes can be nested, a scope points back to its parent scope. A Scope contains information about variables defined in that scope.

See Also:

NodeTraversal

Field Summary

Fields

Modifier and Type	Field and Description
private Var	arguments
protected int	depth
private Scope	parent
protected Node	rootNode
private java.util.Map<java.lang.String,Var>	vars

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Scope(Node rootNode)
(package private)	Scope(Scope parent, Node rootNode) Creates a Scope given the parent Scope and the root node of the scope.

Method Summary

Modifier and Type	Method and Description
(package private) static Scope	createGlobalScope(Node rootNode)
(package private) Var	declare(java.lang.String name, Node nameNode, CompilerInput input) Declares a variable.
java.lang.Iterable<? extends Var>	getAllSymbols()
Var	getArgumentsVar() Get a unique VAR object to represents "arguments" within this scope
Scope	getClosestHoistScope() If a var were declared in this scope, return the scope it would be hoisted to.
int	getDepth() The depth of the scope.
(package private) Scope	getGlobalScope()
Var	getOwnSlot(java.lang.String name) Like getSlot but does not recurse into parent scopes.
Scope	getParent()
StaticScope	getParentScope() Returns the scope enclosing this one or null if none.
Node	getRootNode() Gets the container node of the scope.
Var	getSlot(java.lang.String name) Returns any defined slot within this scope for this name.
Var	getVar(java.lang.String name) Returns the variable, may be null
int	getVarCount() Returns number of variables in this scope (excluding the special 'arguments' variable)
(package private) java.lang.Iterable<Var>	getVarIterable() Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).
<T extends Var> java.util.Iterator<T>	getVars() Return an iterator over all of the variables declared in this scope.
boolean	isBlockScope()
boolean	isDeclared(java.lang.String name, boolean recurse) Returns true if a variable is declared.
boolean	isFunctionBlockScope()
boolean	isFunctionScope()
boolean	isGlobal() Returns whether this is the global scope.
boolean	isLocal() Returns whether this is a local scope (i.e.
java.lang.String	toString()
(package private) void	undeclare(Var var) Undeclares a variable, to be used when the compiler optimizes out a variable and removes it from the scope.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

vars

private final java.util.Map<java.lang.String,Var> vars

parent

private final Scope parent

depth

protected final int depth

rootNode

protected final Node rootNode

arguments

private Var arguments

Constructor Detail

Scope

Scope(Scope parent,
      Node rootNode)

Creates a Scope given the parent Scope and the root node of the scope.

Parameters:

parent - The parent Scope. Cannot be null.

rootNode - Typically the FUNCTION node.

Scope

protected Scope(Node rootNode)

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

createGlobalScope

static Scope createGlobalScope(Node rootNode)

getDepth

public int getDepth()

The depth of the scope. The global scope has depth 0.

getRootNode

public Node getRootNode()

Gets the container node of the scope. This is typically the FUNCTION node or the global BLOCK/SCRIPT node.

Specified by:

getRootNode in interface StaticScope

getParent

public Scope getParent()

getGlobalScope

Scope getGlobalScope()

getParentScope

public StaticScope getParentScope()

Description copied from interface: StaticScope

Returns the scope enclosing this one or null if none.

Specified by:

getParentScope in interface StaticScope

declare

Var declare(java.lang.String name,
            Node nameNode,
            CompilerInput input)

Declares a variable.

Parameters:

name - name of the variable

nameNode - the NAME node declaring the variable

input - the input in which this variable is defined.

undeclare

void undeclare(Var var)

Undeclares a variable, to be used when the compiler optimizes out a variable and removes it from the scope.

getSlot

public Var getSlot(java.lang.String name)

Description copied from interface: StaticScope

Returns any defined slot within this scope for this name. This call continues searching through parent scopes if a slot with this name is not found in the current scope.

Specified by:

getSlot in interface StaticScope

Parameters:

name - The name of the variable slot to look up.

Returns:

The defined slot for the variable, or null if no definition exists.

getOwnSlot

public Var getOwnSlot(java.lang.String name)

Description copied from interface: StaticScope

Like getSlot but does not recurse into parent scopes.

Specified by:

getOwnSlot in interface StaticScope

getVar

public Var getVar(java.lang.String name)

Returns the variable, may be null

getArgumentsVar

public Var getArgumentsVar()

Get a unique VAR object to represents "arguments" within this scope

isDeclared

public boolean isDeclared(java.lang.String name,
                          boolean recurse)

Returns true if a variable is declared.

getVars

public <T extends Var> java.util.Iterator<T> getVars()

Return an iterator over all of the variables declared in this scope.

getVarIterable

java.lang.Iterable<Var> getVarIterable()

Return an iterable over all of the variables declared in this scope (except the special 'arguments' variable).

getAllSymbols

public java.lang.Iterable<? extends Var> getAllSymbols()

getVarCount

public int getVarCount()

Returns number of variables in this scope (excluding the special 'arguments' variable)

isGlobal

public boolean isGlobal()

Returns whether this is the global scope.

isLocal

public boolean isLocal()

Returns whether this is a local scope (i.e. not the global scope).

isBlockScope

public boolean isBlockScope()

isFunctionBlockScope

public boolean isFunctionBlockScope()

isFunctionScope

public boolean isFunctionScope()

getClosestHoistScope

public Scope getClosestHoistScope()

If a var were declared in this scope, return the scope it would be hoisted to. For function scopes, we return back the scope itself, since even though there is no way to declare a var inside function parameters, it would make even less sense to say that such declarations would be "hoisted" somewhere else.